In magnetic recording media, information is written to and read from a recording medium. For example, disk drives may include one or more hard disks, which may be fabricated on production lines.
A hard disk is an apparatus including multiple layers established upon a substrate. For example, a seed layer may be established overlying the substrate. A base layer may be established overlying the seed layer. Perpendicular magnetic recording islands are recording areas that may be established in the base layer and on the seed layer.
Visual inspection tools are used for media production. For example, Candela tools may monitor processes and defect control of hard disk fabrication. The visual inspection tools visually examine a substrate surface, for example the surface of the hard disk, after each layer is established. However, prior to monitoring the hard disk fabrication, the visual inspection tools may need to be reliably and accurately calibrated.